In a liquid crystal display device, a thin film transistor (TFT) is provided at a position at which a gate line (scanning line) and a data line intersect in an active matrix substrate, and the TFT is connected with a pixel electrode. In such a liquid crystal display device, a voltage change in a drain voltage of the TFT, which is called a feedthrough voltage, occurs due to a parasitic capacitance formed between a gate electrode of the TFT and the drain electrode connected with a pixel electrode, when a gate signal shifts from ON to OFF. This causes the potential of the pixel electrode to decreases by the feedthrough voltage. For example, in a case where a display area has a non-rectangular shape such as a circular shape, the lengths of the gate lines are not uniform, the number of data lines intersecting with each gate line varies, and the number of the TFTs connected with each gate line also varies. When differences occur to loads on the gate lines, this makes the waveform dullness different among the gate lines, thereby making the timing when the gate signal shifts from ON to OFF different. As a result, the difference of the timing when the gate signal shifts from ON to OFF causes a difference in the feedthrough voltage, leading to changes in the potentials of the pixel electrodes, and causing display defects such as flicker to occur.
JP-A-2009-69768 discloses a technique of making capacitances of the gate lines uniform in a liquid crystal display device having a circular display area, so as to suppress display defects. On an array substrate disclosed in JP-A-2009-69768, a plurality of scanning lines and a plurality of signal lines are provided. A part of the signal lines are arranged so as to be routed out along peripheral portions of the display area so that all of the scanning lines should intersect with all of the signal lines. In JP-A-2009-69768, capacitances of the scanning lines are made uniform by causing all of the scanning lines to intersect with all of the signal lines.
In the case of JP-A-2009-69768, by causing all of the scanning lines to intersect with all of the signal lines, display defects can be suppressed, but the signal lines have to be routed out along the peripheral portions of the display area. Since driving circuits for driving the scanning lines are also provided in frame areas of the peripheral portions of the display area, the area where the signal lines are arranged is limited. As the area for arranging the signal lines is smaller, the signal lines have to be arranged at narrower intervals, which makes it likely that signal lines would be short-circuited.
It is an object of the present invention to provide a technique of suppressing display defects such as flicker without limiting the arrangement of the data lines, in a liquid crystal display device having a display area having a non-rectangular shape.
A liquid crystal display device in one embodiment of the present invention is a liquid crystal display device including an active matrix substrate, a counter substrate, and a liquid crystal layer interposed between the active matrix substrate and the counter substrate. The active matrix substrate includes: a plurality of gate lines; a plurality of data lines; a plurality of pixel electrodes provided in a plurality of pixels, respectively, the pixels being defined by the gate lines and the data lines; a common electrode provided in a display area composed of the pixels; and capacitance-generating parts that are provided outside the display area, and that generate capacitances between a group of the gate lines among the plurality of the gate lines and the common electrode, wherein the gate lines of the group have a length smaller than that of the gate line having a maximum length, and intersect with a group of the data lines, and the capacitance-generating parts are provided in such a manner that at least one capacitance-generating part is provided with respect to one gate line among the gate lines of the group.
With the present invention, it is possible to suppress display defects such as flicker, without limiting the arrangement of data lines, in a liquid crystal display device having a display area in a non-rectangular shape.